#!/usr/bin/env bash

################################################################################
# Finds changed lines not covered by tests related to changed files.
#
# Usage:
#     check/pytest-changed-files-and-incremental-coverage [BASE_REVISION]
#
# This tool is not clever; it does not understand dependencies between all
# files. If "d/x.py" or "d/x_test.py" have been modified, it will include
# "d/x_test.py" in the arguments given to pytest. It will furthermore include
# "--cov=d" as an argument to pytest-cov, to restrict coverage results to
# directories containing changed files.
#
# You can specify a base git revision to compare against (i.e. to use when
# determining whether or not a line is considered to have "changed"). To make
# the tool more consistent, it actually diffs against the most recent common
# ancestor of the specified id and HEAD. So if you choose 'origin/master' you're
# actually diffing against the output of 'git merge-base origin/master HEAD'.
#
# If you don't specify a base revision, the following defaults will be tried,
# in order, until one exists:
#
#     1. upstream/master
#     2. origin/master
#     3. master
#
# If none exists, the script fails.
################################################################################

# Get the working directory to the repo root.
cd "$( dirname "${BASH_SOURCE[0]}" )" || exit 1
cd "$(git rev-parse --show-toplevel)" || exit 1

# Figure out which revision to compare against.
if [ ! -z "$1" ] && [[ $1 != -* ]]; then
    if [ "$(git cat-file -t $1 2> /dev/null)" != "commit" ]; then
        echo -e "\033[31mNo revision '$1'.\033[0m" >&2
        exit 1
    fi
    rev=$1
elif [ "$(git cat-file -t upstream/master 2> /dev/null)" == "commit" ]; then
    rev=upstream/master
elif [ "$(git cat-file -t origin/master 2> /dev/null)" == "commit" ]; then
    rev=origin/master
elif [ "$(git cat-file -t master 2> /dev/null)" == "commit" ]; then
    rev=master
else
    echo -e "\033[31mNo default revision found to compare against. Argument #1 must be what to diff against (e.g. 'origin/master' or 'HEAD~1').\033[0m" >&2
    exit 1
fi
base="$(git merge-base ${rev} HEAD)"
if [ "$(git rev-parse ${rev})" == "${base}" ]; then
    echo -e "Comparing against revision '${rev}'." >&2
else
    echo -e "Comparing against revision '${rev}' (merge base ${base})." >&2
    rev="${base}"
fi

# Find involved files.
cov_changed_python_file_dirs=$(git diff --name-only "${rev}" -- \
    | grep "\.py$" \
    | grep -v "_pb2\.py$" \
    | xargs -I {} dirname {} \
    | perl -ne 'chomp(); if (-e $_) {print "--cov=$_\n"}' \
    | sort \
    | uniq \
)
changed_python_tests=$(git diff --name-only "${rev}" -- \
    | grep "\.py$" \
    | sed -e "s/\.py$/_test.py/" \
    | sed -e "s/_test_test\.py$/_test.py/" \
    | perl -ne 'chomp(); if (-e $_) {print "$_\n"}' \
    | sort \
    | uniq \
)
if git diff --name-only "${rev}" -- | grep "__init__\.py$" > /dev/null; then
  # Include global API tests when an __init__ file is touched.
  changed_python_tests+=('docs/docs_coverage_test.py')
  changed_python_tests+=('cirq/protocols/json_serialization_test.py')
fi
if [ "${#changed_python_tests[@]}" -eq 0 ]; then
    echo -e "\033[33mNo changed files with associated python tests.\033[0m" >&2
    exit 0
fi

# Run tests while producing coverage files.
check/pytest "${changed_python_tests[@]}" \
    "${cov_changed_python_file_dirs[@]}" \
    --cov-report=annotate \
    --cov-config=dev_tools/conf/.coveragerc \
    --benchmark-skip
pytest_result=$?

# Analyze coverage files.
PYTHONPATH="$(pwd)" python dev_tools/check_incremental_coverage_annotations.py "${rev}"
cover_result=$?

# Clean up generated coverage files.
find . | grep "\.py,cover$" | xargs rm -f

# Report result.
if [ "${pytest_result}" -ne "0" ] || [ "${cover_result}" -ne "0" ]; then
  exit 1
fi
exit 0
